How does income relate to life expectancy?

It’s clear, the rich live longer. But middle-income nations complicate the story

It is widely known that countries with high per-capita wealth have long life expectancies, but just how strong is the correlation across the board? In this video, Hans Rosling, professor of international health at the Karolinska Institute in Stockholm, explores the visual data that details the link between gross domestic product (GDP) and longevity.